Note 10 - Fair Value Measurements (Tables)

9 Months Ended

Sep. 30, 2015

Fair Value Disclosures [Abstract]

Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]

	Fair Value Measurement at September 30, 2015
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	31,135	$	31,135	$	-	$	-
Certificates of deposit		22,008		-		22,008		-
U.S. treasuries and government agency bonds		131,039		-		131,039		-
Auction-rate securities backed by student-loan notes		5,364		-		-		5,364
Mutual funds under deferred compensation plan		3,502		3,502		-		-
Total	$	193,048	$	34,637	$	153,047	$	5,364
Liabilities:
Contingent consideration	$	2,507	$	-	$	-	$	2,507
Total	$	2,507	$	-	$	-	$	2,507

	Fair Value Measurement at December 31, 2014
			Quoted Prices in Active Markets for Identical Assets		Significant Other Observable Inputs		Significant Unobservable Inputs
	Total		Level 1		Level 2		Level 3
Assets:
Money market funds	$	60,078	$	60,078	$	-	$	-
Certificates of deposit		22,778		-		22,778		-
U.S. treasuries and government agency bonds		89,674		-		89,674		-
Auction-rate securities backed by student-loan notes		5,389		-		-		5,389
Mutual funds under deferred compensation plan		2,236		2,236		-		-
Total	$	180,155	$	62,314	$	112,452	$	5,389
Liabilities:
Contingent consideration	$	2,507	$	-	$	-	$	2,507
Total	$	2,507	$	-	$	-	$	2,507

Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block]

Balance at January 1, 2015	$	5,389
Change in unrealized loss included in other comprehensive income		(25	)
Ending balance at September 30, 2015	$	5,364

Schedule of Level 3 Assumptions [Table Text Block]

	September 30,			December 31,
	2015			2014
Time-to-liquidity (months)		24			24
Expected return		2.5%			2.9%
Discount rate	3.9%	-	6.9%	4.0%	-	7.0%